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PROCESS OP TEMP-BRING WIRE SPRINGSyxizbc.-`

Patented Apr. 7, 1885.

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UNITED STATES MELvIN NEWTON LOvELL, OF ERIE,

PATENT f OFFICE.

PENNSYLVANIA, AssIGNOE 'ro `THE. LOvELL MANUFACTURING COMPANY, (LrMrrEu)OF SAME PLAGE.

PROCESS OF TEMPERING -w|RE SRRlNeS, sw.

SPECIFICATION forming part of Letters Patent No. 315,424,1dated April 7,1885.

Appncflmi fixed Apfiriv, 1884. (No modell) To all whom t may concern: i

Be it known that I, 'MELVINN' LOVELL, a` citizen of the United States,residing at Erie, in the county of Erie and State of Pennsyl. vania,have invented certain new and useful Improvements in Process VofTempering Wire Springs and other Small Articles;` and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art towhich. itappertains to make and use the same.

This invention consists in improvements in the process of tempering wiresprings-Euch, for example, as furniture-springs-and also other smallobjects, whether made of wire orl I shall in the following 'descriptioniirst describe an apparatus by means of which my process is carried out,and then clearly point out the essential features of the process.

My apparatus consistsof an oven, which is so constructed that the plateson `one side of it are much hotter than on the other side, and arevolving wheel within said oven conveys the article to be tempered infront ofthe said plates from the coolest to the hottest points, thusexposing the article to' a gradually-increasing temperature until it hasbecome sufficiently heated. This apparatus is shown in the accompanyingdrawings, as follows:

Figure l is a longitudinal vertical section through the oven and itsfurnace. Fig. 2 is a transverse vertical 'section' through the sameparts.

A is the masonry forming theoven and furnace. A is thecombustion-chamber or reboX. A2 is a diving-nue which passes around theunder side of the oven. A3 is the chimneyiiue. Bis the oven-chamber,which is formed on top by an arch in the masonry and on the bottom andsides of iron plates C C Gwhich rest on a ledge in the masonry. D is theconveyer-wheel, which is rotated in the oven in the direction indicatedby an arrow thereon. d d d, Snc., are holes in the side of said wheel. dd d', are rods which are set into said holes, and on which the articlesto be tempered are n S S represent bed-springs nested together and hungon said rods. E E (shown only in dotted lines in Fig. l, as they are inthe wall which is removed by the section) are l theopenings throughwhich the articles enter and are removed from theoven. F is an openingwith adoor, by which access maybe had tothe bottom of the oven, ifrequired. This,

-too, is in the'wall removed, and is shown by dotted lines. D is.theshaft of the wheel D,

and DZ D3 is the gearing by which the Wheel -is rotated.

This device was designed and so far has only but it is obvious thatitheed not be limited to that use, but may be employed for temperingalmost any article that is made of light metal which will becomethoroughly heated by the exposurehere obtained. AIf the articles are notof such a form as to hang on the rodsdf, l they can beprovidedwit-h'means for hanging In the drawings I have shown fur-` themon. niture-springs as the articles being operated upon, andastheoperation would be the same with any other article I shallhereinafter speak only of springs. Y Y

'The re as it is applied to the plates heats the plate C, which is 'nextto and forms the back of the irebox, the hottest. The plate 'C' will notbeso hot as C, and the plate C2 will A There will be several hundred bestill cooler.

degrees difference between the temperature of the plates C and C2;hence, of course, the oven will be cooler on the side, next the plateC2,

and its hottest point will be directly opposite the fire-box. Y

The springs are nested together,

tongs and inserts -it into the oven endwise about a` dozen in each nest,and are strung onto a rod, .dwhich the attendant grasps with a pair ofthrough vthe door E, on the right of Fig. l,

and sticks the end of the rod into one of the holes d in the wheel D. Aswill be seen by the arrow, the wheel rotates from the door E rate I havenamed it takes about thirteen minutes for the springs to pass from thedoor Thewheel oo vbeen used Vfor tempering furniture-springs;

E down and up to the door E, when they are removed by the attendantgrasping the rod d with his tongs and drawing it out. The wheel moves soslowly that holes d can be placed quite near together, and the attendantwho puts in will be able to place a rod in each hole, and the attendantwho takes out will have no difficulty in removing all the rods as theycome opposite door E. rIhus it will be seen the work goes oncontinuously. The springs enter at the coolest point and are removed ina few minutes at the hottest point.

For furniture-springs I have found that I obtained the best results bykeeping the re so that the plate C is kept at a cherry-red heat. Thisgives about 1,200o Fahrenheit at the hottest point in the furnace, sothat the springs are heated to nearly that temperature when they areremoved.

It should be observed, for it is an essential feature, that the springsare so held by the wheel and the rods that each nest of springs obtainsprecisely the same exposure to the heat as the others do.

I am aware that springs have been heated before in an oven by beinglconveyed by a conveyer-wheel, or, rather, an upright shaft with arms;but the furnace was below the oven, and the springs which were placed onthe lowest arms of the conveyer were heated more than those placed onthe upper arms, and the springs when put in were exposed at once to thesame degree of heat th at they were exposed to during all their stay inthe oven.

It is not necessary to obtain the result I do that the wheel and ueshave the same position I show. The wheel might be made so as to revolvehorizontally, and the flues made so as to pass around one side of theoven; but such a change would gain nothing in effeet, but would lose inconvenience. The form I show is exceedingly convenient to operate, andthe fines are so disposed as to get the best application of the fire tothe plates.

When the springs are removed from the oven, they are plunged at onceinto cold water or other cooling-bath. My process, therefore7 is asfollows: Placing the springs in an oven from which the products ofcombustion are excluded at a point having a less degree of 5o heat thanother parts of the oven, progressing them gradually through pointshaving greater heat than where they entered, and when they have reachedthe highest degree of heat remove them and plunge them at once into acooling-bath.

It is obvious that various other means could be used for carrying out myimproved process; for example, a horizontal chamber having a travelingcar or endless carrier might be substituted for the means shown; but forcoiled springs I prefer the means herein shown, as I have 'found inpractice the best results are thereby obtained. Y

I do not claim in this application the apparatus for tempering springsand other articles as herein described, as that forms the subjectmatterof an application filed March 16, 1885, Serial No. 159,071.

I am aware that it is old to subject articles to be tempered to agraduallyincreasing heat in a flue or chamber through which the productsof combustion are passed; but articles so subjected absorb sulphur andother impurities from the products of combustion, and thus depreciatetheir value. By my process these defects are obviated, as the articlesare treated in a chamber from which the products of combustion areexcluded.

Vhat I claim as new is- The process herein described for temperingsprings and other light articles-viz., inserting lsaid articles in anoven-from which the products of combustionare excluded-at a part oftheoven where the heat is considerably below the final heat required,advancing them gradually by a conveyer to that part of the oven wherethe heat is brought to the degree specified, and then immediatelywithdrawing and plunging them into a cooling-bath, substantially as setforth.

In testimony whereof I affix my signature XVitnesses:

FRANK Gunnison, ROBERT H. PORTER.

